Interactive RadioEpidemiologicalProgram (NIOSH-IREP)

• Uses updated cancer risk models including uncertainty from epidemiologic data.

• Includes 33 cancer types and accounts for:• Radiation Dose• Gender• Age of Exposure• Date of Cancer Diagnosis • Other Factors (smoking for lung)

• Probability of Causation is calculated by dividing the risk from radiation by the combined risk from radiation and background incidence.

• Radiation Effectiveness Factors• Account for differences in risk 

between leukemia and solid tumors from different radiation types and energies

• 4 Radiation types with different energy intervals

• Dose and Dose Rate Effectiveness Factor (DDREF)• Uncertainty distribution for 

reduced risk from low-LET radiation received at a low rate.

• Uncertainty distribution for increased risk from high-LET radiations received at a low rate (inverse dose rate effect)

Procedures for Multiple Primary Cancers

• Probability of causation for multiple cancers is calculated by determining the probability of causation for each cancer and then combining the probabilities as follows:

Guidelines for Determining the Probability of Causation under the U.S. Energy Employees Occupational Illness 

Compensation Program Act (EEOICPA) of 2000Mary Schubauer-Berigan, Larry J. Elliott, Ted Katz, and James Neton

U.S. Department of Health and Human Services (DHHS), Centers for Disease Control and Prevention (CDC), National Institute for Occupational Safety and Health (NIOSH), 4676 Columbia Parkway MS: R-45, Cincinnati, Ohio 45226

DISCUSSIONINTRODUCTION

CONCLUSIONS

Guidelines for Determining Probability of Causation (42CFR Part 81)

• Based on the cancer risk models developed by the National Institutes of Health (NIH) in 1985.

• Cancer risk models updated by a joint workgroup of the National Cancer Institute and the Centers for Disease Control and Prevention (CDC).  • New cancer risk models are 

based on cancer incidence rather than cancer mortality.

• NIOSH-Interactive RadioEpidemiological Program (NIOSH-IREP) developed for probability of causation calculations.• Accounts for uncertainty 

associated with  radiation dose and cancer risk models.

• Radiation Effectiveness• Dose and Dose-Rate 

Effectiveness

• Provide the Department of Labor with  systematic objective procedures for handling claims with unusual characteristics.• Multiple Primary Cancers• Primary cancer identification 

from secondary cancers

...])1()1[(121×−×−−= CancerCancer PCPCPC

%100xBaseRiskRadRisk

RadRiskPC+

=

METHODS

Primary Cancer identification from Secondary Cancers

• Guidelines based on evaluation of National Center for Health Statistics (NCHS) Mortality Database.

• For each secondary cancer, the set of primary cancers producing approximately 75% of the secondary cancer was identified.

• Final assignment of a primary cancer determined by the Department of Labor as the site among possible primary sites which results in the highest probability of causation.

> 15 keVAll EnergiesAlpha Particles

< 15 keVElectrons (Beta Particles)

> 20 MeV2 MeV – 20 MeV

100 – 2 MeV10 – 100 keV

< 10 keV

Neutrons

> 250 keV30-250 keV

< 30 keVPhotons

EnergyRadiation Type

• Regulation provides a fair, reasonable, and science based approach by which the Department of Labor can determine whether an energy employees cancer was “at least as likely as not”  (50% or greater probability) caused by radiation doses incurred in the line of duty.

Probability of Causation0 10 20 30 40 50 60 70 80 90 100

Freq

uenc

y D

istr

ibut

ion

0

50

100

150

200

250

300

99% Upper Confidence IntervalPC = 60.9%

Median  PC = 28.7%

• Determinations based on upper 99% confidence interval (credibility limit) of the probability of causation

• Minimizes the possibility of denying compensation to claimants with cancers likely to have been caused by radiation exposures